516 



BURYING OF FOSSILS IN 



[Ch. XLV. 



others^ - at least all the 



com 



easily 



broken by tbe movements of earthquakes^ which would 

 produce only flexures in argillaceous strata. Eissures once 

 formed in limestone are not liable, as in many other forma- 

 tionSj to become closed up by impervious clayey matter, and 

 hence a stream of acidulous water might for ages obtain a 

 free and unobstructed passage.^ 



Morea 



■Nothing is more common in limestone districts 



than the engulfment of rivers, which after holding a sub- 



many miles 



outlet. 



sediment 



often with sand and pebbles where they enter, whereas they 

 are commonly pure sftid limpid where they flow out a 

 they must deposit much matter in empty spaces in the 

 interior of the earth. In addition to the materials thus in- 

 troduced, stalagmite, or carbonate of lime, drops from the 

 roofs of caverns, and in such mixture the bones of animals 

 washed in by rivers are often entombed. In this manner we 

 may account for those bony breccias which we often find in 

 caves, some of which are of high antiquity while others are 

 very recent and in daily progress. In no district are engulfed 

 streams more conspicuous than in the Morea, where the 

 phenomena attending them have been studied and described 

 in great detail by M. Boblaye and his fellow-labourers of the 

 French expedition to Greece. f Their account is peculiarly 

 interesting to geologists, because it throws light on the red 

 osseous breccias containing the bones of extinct quadrupeds 

 which are so common in almost all the countries bordering 

 the Mediteiranean. It appears that the numerous caverns 

 of the Morea occur in a compact limestone, of the age of 

 the English chalk, immediately below which are arenaceous 

 strata referred to the period of our greensand. In the more 

 elevated districts of that peninsula there are many deep 

 land-locked valleys, or basins, closed round on all sides by 

 mountains of fissured and cavernous limestone. The year is 

 divided almost as distinctly as between the tropics into a 

 rainy season, which lasts upwards of four months, and a 



^ See remarks by M. Boblaye, Ann. 



t Ann. des Mines, 3me serie, torn, iv 



dos Mines, 3nie serie, torn. iv. 



1833. 



) 



i 







> 



